Chemical analysis apparatus and chemical analysis method

ABSTRACT

A chemical analysis apparatus in which a sample to be analyzed and a reagent are placed into a reaction container, and sound waves are irradiated to said reaction container so as to agitate them, wherein said chemical analysis apparatus comprises a piezoelectric element producing said sound waves, and drivers for driving said piezoelectric element, said sound waves being intermittently irradiated into said reaction container.

CROSS REFERENCE TO RELATED APPLICATION

This is a divisional of U.S. application Ser. No. 10/347,384, filed Jan.21, 2003. This application relates to and claims priority from JapanesePatent Application No. 2002-055178, filed on Mar. 1, 2002. The entiretyof the contents and subject matter of all of the above is incorporatedherein by reference.

BACKGROUND OF THE INVENTION

The present invention relates to a chemical analysis apparatus, and inparticular to a chemical analysis apparatus incorporating an agitatingmechanism for mixing a reagent and a sample with each other within areaction container.

JP-A-8-146007 discloses a method of agitating a sample and a reagent ina noncontact manner by irradiating ultrasonic waves toward an opening ofa reaction container containing therein the sample and the reagent, froma position below the container in order to mix the sample and thereagent with each other in a noncontact manner with no use of a spatulaor a screw.

Further, JP-A-2000-146986 discloses such a technology that sound wavesare irradiated to a reaction container containing therein a substance tobe agitated (a sample and a reagent), laterally of the container, inorder to agitate the substance in the container, in addition toirradiation of sound waves to the container toward the opening of thecontainer from a position below the container.

Further, JP-A-2001-242177 discloses such a configuration that the meansfor irradiating sound waves to the container from a position below thecontainer, which is disclosed in the JP-A-2000-146986 is a reflectingplate.

However, in such a case that a substance using a bit of a sample isefficiently agitated in a container so as to carry out an analysis, ithas been found that the well-known above-mentioned configurations areinsufficient. For example, with a configuration in which sound waves areirradiated from a position below the container toward the opening of thecontainer, or sound wave are irradiated from one side of the container,should strong sound waves be irradiated from a sound wave supply meanswhich is disclosed in the above-mentioned documents and which is locatedbelow the container in order to apply a strong agitating power, theliquid surface of the sample would swell upward so as to cause such arisk that a sample solution scatters. On the contrary, should weak soundwaves be irradiated, no contribution to sufficient agitation would beobtained.

BRIEF SUMMARY OF THE INVENTION

The present invention is devised in order to solve the above-mentionedproblems inherent to prior art, and accordingly, an object of thepresent invention is to provide a chemical analysis apparatusincorporating a mechanism for efficiently agitating a substance to beagitated.

To the end, according to a general concept of the present invention,there is provided such a mechanism that sound waves are irradiated to asubstance to be agitated in a container in several directions in which awall of the container is laid behind the substance to be agitated.

Specifically, according to a first aspect of the present invention,there is provided a chemical analysis apparatus incorporating a placingportion in which a reaction container containing therein a substance tobe analyzed is placed, a sound wave supply portion spaced from thesubstance to be analyzed, for irradiating sound waves to the substanceto be analyzed, and a measuring portion for measuring physicalproperties of the substance to be analyzed, characterized in that afirst sound wave fed from the sound supply portion is irradiated to aposition corresponding to a first part of the reaction container, asecond sound wave is irradiated to a position corresponding to a secondpart of the reaction container, and the first and second sound waves areirradiated from a position where a wall of the reaction container islocated behind the substance to be analyzed, as viewed in a direction inwhich the sound waves are propagated.

In a first specific form of the first aspect of the present invention,the chemical analysis apparatus is characterized in that the first partis the one in which an interface of a fluid including the substance tobe analyzed, contained in the reaction container, is defined, and thesecond part is the one which is located, being off from the first partto the bottom side of the reaction container. For example, in the caseof liquid, it is not a part where the liquid is made into contact withthe container, but a part where the liquid defines a liquid surface.

In a second specific form of the first aspect of the present invention,the second sound wave is the one which is reflected by a reflectingmeans. This reflecting means is adapted to irradiate a sound wavereflected below the sound waves fed from the sound wave supply portion.

In a third specific form of the first aspect of the present invention,the first sound wave is fed from a first sound wave supply portion, andthe second sound wave is fed from a second sound wave supply portion.

In a fourth specific form of the first aspect of the present invention,the reflecting means comprises a reflecting plate having a sound wavereflecting surface which is concave. Alternatively, the reflecting meansis adapted to reflect reflected sound waves which are converged toward azone where the reaction container is placed.

In a fifth specific form of the first aspect of the present invention,the sound wave supply portion is formed of a single piezoelectricvibrator having an outer surface formed thereon with an electrode whichis split.

In a sixth specific form of the first aspect of the present invention,there is further incorporated a mechanism for changing the energy of thesound waves irradiated to the substance to be analyzed.

According to a second aspect of the present invention, the first soundwave irradiated to a position at which the reaction container is placed,is fed from a location that is spaced from a location where the secondwave irradiated to the position at which the reaction container isplaced, is fed, the reaction container intervening between twolocations.

According to a third aspect of the present invention, the first soundwave irradiated to a position at which the reaction container is place,is fed from a location that is spaced from a location where the secondwave irradiated to the position at which the reaction container isplaced, is fed, the reaction container intervening between twolocations. Further, the reaction container is placed between the firstsound wave supply portion and the second sound wave supply portion.

As mentioned above, in the present invention, there is provided a meansfor mixing a sample and a reagent in a noncontact manner, in thechemical analysis apparatus incorporating, for example, a reactioncontainer having an opening, sample, reagent and diluent supply meansfor supplying the sample, the reagent and diluent into the reactioncontainer through the opening thereof so as to obtain a solution to bemeasured in the reaction container, and a means for measuring physicalproperties of the solution to be measured during reaction or aftercompletion of the reaction. This mixing means is provided outside of thereaction container, and is provided with a sound wave producing meansfor irradiating sound waves in parallel with a liquid surface of thesolution to be mixed in the reaction container, or obliquely to theliquid surface in a direction from a liquid phase to a gas phase, ameans for reflecting sound waves passing through the solution to bemeasured, so as to introduce the reflected sound wave again into thereaction container, and a mechanism for producing the sound waves whilechanging their energy. With this arrangement, the mixing of the sampleand the reagent can be effective in a non-contact manner.

Other objects, features and advantages of the invention will becomeapparent from the following description of the embodiments of theinvention taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

FIG. 1 is a perspective view illustrating an entire configuration of achemical analysis apparatus in an embodiment of the present invention;

FIG. 2 is a vertically sectional view illustrating a part of theembodiment illustrated in FIG. 1, in detail;

FIGS. 3 a to 3 b are views for explaining a fluidization principleduring agitation in the chemical analysis apparatus according to thepresent invention;

FIGS. 4 a to 4 c are sectional views illustrating various possibleconfigurations of a reflector shown in FIG. 2;

FIGS. 5 a to 5 b are views for explaining a sound source in the chemicalanalysis apparatus according to the present invention;

FIGS. 6 a to 6 b are views for explaining the operation of a drivesystem for the sound source in the chemical analysis apparatus accordingto the present invention;

FIG. 7 is a schematic view illustrating another embodiment of thepresent invention;

FIG. 8 is further another embodiment of the present invention;

FIG. 9 is further another embodiment of the present invention; and

FIG. 10 is further another embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Explanation will be hereinbelow made of embodiments of the presentinvention with reference to the accompanying drawing. It is noted thatthe present invention should not be limited only to configurations ofthe embodiments which will be explained, but the present invention canhave any other various configurations.

A chemical analysis apparatus in these embodiments may be composed of anautomatic sample pipetting mechanism for feeding a sample to be analyzedinto a reaction container, an automatic reagent pipetting mechanism forfeeding a reagent into the reaction container, an automatic agitatingmechanism for agitating the sample and the reagent in the reactioncontainer, a measuring unit for measuring physical properties of thesample during reaction or after completion of the reaction, an automaticwashing mechanism for sucking and discharging the sample after themeasurement, and for washing the reaction container, and a controlmechanism for controlling the operation of the above-mentionedcomponents.

Explanation will be made of a first embodiment of the present inventionwith reference to FIGS. 1 and 2. FIG. 1 is a perspective viewillustrating a configuration of a chemical analysis apparatus in thefirst embodiment of the present invention, and FIG. 2 is a verticallysectional view illustrating a configuration of an agitating mechanism ofnon-intrusion type (non-contact type) incorporated in the chemicalanalysis apparatus of the first embodiment shown in FIG. 1, foragitating and mixing a substance to be agitated, in a non-contactmanner.

The chemical analysis apparatus in the first embodiment is mainlycomposed of a reaction disc 101 for accommodating reaction containers102, a constant temperature tank 114 for holding a constant temperaturecondition of the reaction containers accommodated in the reaction disc,a sample turntable 103 for accommodating sample cups 104, a reagentturntable for accommodating reagent bottles 105, a sample pipettingmechanism 107 for pipetting a sample into a reaction container, and areagent pipetting mechanism 108 for pipetting a reagent into thereaction container, an agitating mechanism 109 for agitating thepipetted sample and reagent in the reaction container 102, an opticalmeasuring mechanism 110 for measuring a light absorbance of the mixedsubstance in the reaction container during a reaction process or afterthe reaction process, and a washing mechanism 111 for washing thereaction container after the measurement (of light). The above-mentionedcomponents are operated under control by a program which isautomatically prepared by the controller 112 in accordance with data(analysis items, a liquid quantity to be analyzed and the like) which ispreviously set up on a console 113 before the measurement is initiated.

The above-mentioned agitating mechanism 109 is composed of, as shown inFIG. 2, a sound wave producing means 201 (which will be referred tosimply as “a sound source”) provided, external to and lateral of thereaction container 102, and a sound wave reflecting means 202 (whichwill be referred to simply as “reflector”) for reflecting sound wavespropagated through the reaction container so as to introduce the soundwave again into the reaction container. The sound source has such astructure that segments 501, 503 are arranged in an array, as shown inFIGS. 5 a and 5 b so that they can be driven, independent from eachother, and accordingly, those of the segments which are appropriate areselected by drivers 504, 506 through the intermediary of switches or thelike in order to irradiate sound waves from an optional position 502.Further, the driver is composed therein of, as shown in FIG. 6 a whichis a block diagram, a wave form producing device 601 for producing anoscillation waveform 602 having a fundamental frequency of sound wavesto be irradiated, and an auxiliary waveform producing device 603 forproducing an oscillation wave form 604 having a frequency lower thanthat of the oscillation waveform 602, a multiplying circuit 605 forcreating a multiplied waveform 606 between the both waveforms 602, 604,and a power amplifier 607 for power-amplifying the multiplied waveform606. The above-mentioned driver is adapted to apply a voltage 608 whichhas been amplitude-modulated to piezoelectric elements.

Explanation will be hereinbelow made of the operation of theabove-mentioned chemical analysis apparatus. A sample is pipetted from asample cup 104 into a reaction container 102 by means of the samplingmechanism 107. Next, the turntable accommodated therein with thereaction container 102 is turned so that the reaction container 102comes to a reagent pipetting position where a reagent is pipetted intothe reaction container from a reagent bottle 106 by means of the reagentpipetting mechanism 108. Further, the turntable is turned so that thereaction container 102 comes to a position where the agitating mechanism105 is provided, and where the sample and the reagent in the reactioncontainer are agitated. After completion of the agitation, measurementsare started, and after completion of the reaction the mixture of thesample and the reagent is sucked up by the washing mechanism 111 forwashing the reaction container. The above-mentioned process steps inseries are successively carried out for each of a plurality of samplesin a batch.

Next, explanation will be made of the operation of the apparatus foragitating a substance to be agitated in the reaction container in anoncontact manner with reference to FIG. 2 which is a verticallysectional view illustrating the agitating device. There is provided asound wave producing portion (which is a sound wave reflecting means 202in this embodiment) for irradiating sound waves to the lower part of thereaction container in order to agitate a solution including a sample inthe reaction container. Specifically, for example, there may be providedsuch a configuration that the reaction container 102 is located betweenthe sound wave producing means 201 and the sound wave reflecting means202. In this embodiment shown in FIG. 2, sound waves produced from thesound wave producing means 201 are reflected by the sound wavereflecting means 202 located on the opposite side, and are then fed intothe reaction container. Next, explanation will be made of the basicoperation thereof. A driver circuit 205 incorporating a driver andswitches for the sound source, connected to the main controller 112 forthe entire apparatus, receives data 206 relating to a quantity of asolution to be agitated, that is, a quantity of the sample and thereagent which have been pipetted in the reaction container, and a timingfor agitating thereof. At first, the driver circuit 205 calculates aheight 208 of the liquid surface of a solution to be measured, which ischarged in the reaction container, from data relating to the liquidquantity in order to determine an optimum sound wave irradiating zoneincluding the liquid surface, and selects segments 207 in the soundsource, corresponding to the irradiating zone in order to drive thesound source. Since the driver circuit causes a piezoelectric element inthe sound source to deliver a voltage having a waveform which has beenamplitude-modulated, the sound wave to be irradiated are produced inaccordance with variations in the amplitude thereof. The irradiatedsound waves are propagated to the reaction container through theconstant temperature bath 204, and are introduced into the reactioncontainer. In general, if sound waves which have been propagated throughliquid comes to a free liquid surface, a force with which liquidscatters into a gas phase is exerted (which is mainly caused by acousticradiation pressure) to the liquid. At this stage, in this embodiment,since the voltage having a waveform which has been amplitude-modulatedis delivered the sound source from the driver circuit, the sound wavesto be irradiated are also dependent upon variation in the amplitudethereof. It is noted that the sound waves which are introduced into thereaction container after reflection, are propagated in a directiontoward a position where no liquid surface is present.

Further, the sound reflecting means 202 is provided behind the reactioncontainer in the direction of propagation of the sound waves, withrespect to the sound wave producing means 201, and accordingly, it ispossible to restrain the sound waves produced by the sound waveproducing means 201 from causing damage to peripheral equipment, or thelike.

If an intermittent sound wave 201 is irradiated as shown in FIG. 3 a,the force is exerted to the liquid surface so as to crease a kind of awave on the liquid surface in the reaction container. Further, the soundwave 301 is irradiated in a beam-like shape having an intensitydistribution 303 as shown in the figure, and accordingly, a part thereofis transmitted through the reaction container as indicated by the dottedline. The transmitted sound wave is reflected by the reflector 202, andis again introduced (203) into the reaction container. By the way, sincea sound flow or an acoustic radiation pressure is produced when soundwaves are propagated through liquid, the reintroduction of thetransmitted sound wave causes such an effect that the liquid isfluidized in the sound propagating direction. At this time, thedirection of the propagation of the sound wave which is reintroducedinto the reaction container is set so as to be not directed toward theopening of the container (that is, for example, toward a position whereno liquid surface is present), and accordingly, it is possible torestrain the liquid from scattering outside of the reaction containereven though the intensity of the sound wave is increased. Due to thefluidization of the liquid accompanied with the wave produced at theliquid surface, and the fluidization caused by the reintroduction of thesound wave through the reflection, the liquid is fluidized as indicatedby the arrow 302. With the repetitions of irradiation of theabove-mentioned intermittent sound wave, a swirl flow 305 is produced inthe liquid in the reaction container as shown in FIG. 3 b. In thechemical analysis apparatus according to the present invention, there isused a means for mixing a sample and a reagent with the use of the swirlfluidization in a noncontact manner with respect to the liquid.

With the configuration of this embodiment, it is possible to prevent theliquid from scattering in comparison with such a case that sound wavesare irradiated from a position external to and below the reactioncontainer toward the opening of the latter. Further, the agitation inthis embodiment is effective by applying a suitable sound intensitydistribution to the liquid to be measured within the reaction container.Further, in this embodiment with the use of the fluidization whoseacoustic radiation pressure is dominant in the vicinity of a liquidinterface which is not affected by a friction of the wall surface of thereaction container, the liquid to be measured can be agitated and mixedby sound waves having a smaller intensity in comparison with such amethod which utilizes only acoustic fluidization. Further, since soundwaves having propagated through the reaction container is againreintroduced into the latter so as to promote the fluidization in thebottom part of the reaction container, the produced sound waves can beeffectively used.

Further, since the mixing can be made with a completely noncontactmanner with respect to the liquid to be measured contained in thereaction container, agitation with carry-over-less and a bit of liquidcan be carried out in a chemical analysis apparatus. Thereby it ispossible to materialize a function capable of performing high speedanalysis.

Further, it is possible to provide a configuration which is preferablefor several inspection items which can accept reagents and samples whichhave liquid quantities and liquid physical properties in a wide range.

Further, it is possible to carry out the agitation with carry-over-lessand a bit of liquid, and to reduce the consumption power.

Further, it is possible to avoid problems including carry-over andcontamination caused by sticking inherent to an agitating process withthe use of a spatula or a screw, and positioning accuracy caused byminiaturization of the reaction container.

It is specifically noted that since a sample can be agitatedeffectively, if the present invention is applied in a chemical analysisapparatus capable of performing a high speed process with a high degreeof accuracy, in which several samples can be analyzed in a batch with ashort time, the time by which a result of an inspection can be obtainedafter the inspection is completed can be shortened.

Further, even though a sample extracted from a patient or the like isreduced, the sample can be effectively agitated. Thereby it is possibleto reduce the quantity of waste liquid to be disposed after theinspection, and further, it is possible to reduce the running costs forthe inspection.

It is noted that a sample and a reagent are automatically pipetted intoeach of reaction containers circumferentially accommodated in the turntable by a pipetter incorporating a robot arm, and a solution to bemeasured (the sample and the agent which have been pipetted into thereaction container) is mixed by means of the agitating mechanism.Further, a chemical reaction of the solution is measured, and the resultof the inspection thereof is outputted. After completion of themeasurement, the solution to be measured is sucked, and then, thereaction container is washed. Thus, the inspection of the sample iscompleted for one of several items thereof. Practically, in general,with the use of a chemical analysis apparatus capable of performing sucha process that a plurality of inspections are carried out in sequenceunder control programmed by the user, of several manipulation steps(pipetting and agitating of the sample and the reagent, and washing ofthe reaction container), the step of agitating the solution to bemeasured can be effectively made, that is, it is possible to suppressdeficiencies such as that no desired reaction can be fulfilled due toinsufficient mixing caused by short-time agitation, and accordingly,precise inspection results cannot be obtained. Further, in the case ofusing a spatula for agitation, should a bit of a solution which has beenused during inspection be carried by the spatula into a reactioncontainer for a next inspection (carry-over), the problem ofcontamination would be caused. Thus, it is possible to prevent thesolution to be measured from being decreased due to sticking to thespatula.

In the configuration disclosed in the above-mentioned JP-A-8-146007, insuch a case that sound waves are irradiated to a reaction container froma position external thereto so as to apply a suitable sound intensitydistribution in a substance to be agitated in the reaction container inorder to induce acoustic fluidization, the smaller the quantity of asolution to be measured, the smaller the reaction container itself,resulting in reduction of the surface area of the reaction container,acoustic energy required for generating the acoustic fluidization canhardly be applied to the substance in the reaction container. Further,in order to create a circulation flow which is effective for theagitation, it is required to create a sharp intensity distribution ofthe sound field in the reaction container. However, in the case of asmall-sized reaction container, relative intensity difference in thesound field is decreased, and accordingly, it is difficult toefficiently agitate the solution to be measured in a short time.

Next, detailed explanation will be made of the distinct features of thesound source and the drive system (around the drive circuit) which areused in this embodiment. Referring to FIG. 5 a which shows the arrayedsound source as mentioned above, this embodiment utilizes such aconvenient way that one of electrodes on both sides of a singlepiezoelectric element is divided into several parts 501. These dividedelectrode parts are selectively applied with a voltage 504,corresponding to a desired irradiating zone as shown in FIG. 5 b, andaccordingly, there can be materialized a sound source which isfunctionally equivalent to sound sources which are arranged in an array.It is noted that a part of the electrode on the side where the electrodeis not divided is folded back onto the surface of the piezoelectricelement on the side where the electrode is divided, as indicated by 505,the connection of electric wires from drivers can be concentrated toonly one surface thereof. With the use of the single piezoelectricelement applied with the electrodes which are fabricated as mentionedabove, the costs of the agitating mechanism can be reduced. Theconfiguration of this sound source is advantageous in view of the massproduction base thereof, and with the use of an electrode patternproduced by screen printing or the like, the time required formanufacturing the agitating mechanism can be shortened. Further, sincethe structure thereof is relatively simple, the agitating mechanism ishighly reliable. Further, in comparison with a conventional spatulaincorporating a robot arm, the size of the agitating mechanism can begreatly reduced, thereby it is possible to contribute to miniaturizationof the entire apparatus.

In this embodiment, with the provision of such a feature that pulsationcan be applied to a swirl flow in the reaction container by changing, intime, the intensity of ultrasonic waves to be irradiated in theagitating mechanism, the mixing can be enhanced thereby so as to shortenthe time required for the agitation, and to save consumption power.

As to a wave form which is used as a subwaveform for amplitudemodulation, there may be used a rectangular waveform which repeatsturn-on and -off as shown in FIG. 6 b, in addition to a waveform asshown in FIG. 6 a, in which it sinusoidally varies between its minimumvalue and its maximum value. In this case, a relatively simplifiedwaveform creating mechanism can be used, thereby it is possible toreduce the costs of the driver. Further, the above-mentioned turn-on and-off operation can be made only by turning on and off the driver whichproduces only a fundamental frequency of sound waves, thereby it ispossible to further reduce the costs of the driver.

Further, as to another measures for saving consumption power, there maybe used such a method that the reflecting surface of the reflector 202is fabricated. FIGS. 4 b and 4 c are sectional views along line A-Bshown in FIG. 4 a, illustrating the reaction container 102 and thereflector 202 which have been explained hereinabove. Specifically, FIG.4 b shows a pattern of sound rays in which sound waves 401 irradiatedfrom the left side of the figure is propagated through the reactioncontainer, and is reflected by the reflector so as to be againintroduced into the reaction container. As shown in Figure, since thereflecting surface is fabricated in a spherical shape, reflected soundwaves can be converged to one single point due to an effect similar tothat of a parabola antenna. Since the intensity of the sound waves isincreased, correspondingly, at a position where the sound waves areconverged, if the converged point is set to a suitable position (forexample, the center of the reaction container), the fluidization with ahigh degree of efficiency can be obtained. FIG. 4 c shows an example inwhich the sound waves 403 propagated outside of the reaction containerare reflected toward the reaction container. In this case, the surfaceat which the propagated waves are reflected, is set to be perpendicularto the propagated waves, and a surface at which the sound waves 403propagated outside of the reaction container is reflected is fanned soas to direct the reflected waves toward reaction container. In either ofthe cases, the sound waves 403 propagated outside of the reactioncontainer can be effectively used, and can be also converged togetherwith the sound waves propagated through the reaction container, therebyit is possible to enhance the intensity of the sound waves to bereintroduced into the reaction container.

In the case of using a piezoelectric element in a sound source, theremay be used a thickness resonance of the piezoelectric element. In thecase of manufacturing such a sound source on a mass production base,unevenness among piezoelectric elements would be possibly serious due totrade-off between manufacturing costs and machining accuracy. Referringto FIG. 6 b which schematically shows frequency response characteristicsof three piezoelectric elements (they are fabricated with their uneventhicknesses) around their thickness resonances, it will be found thatuneven thicknesses of piezoelectric elements cause uneven resonantfrequencies with which the piezoelectric elements produce output powerswith maximum intensity. Accordingly, such a problem that unevennessamong piezoelectric elements would be serious can be solved by frequencymodulation to the frequency of sound waves around their resonantfrequencies. In the above-mentioned embodiment, although the waveformproducing device 601 for producing the oscillation frequency wave 602having a single frequency has been explained, with the provision of afunction capable of frequency-modulation around a resonant frequencywith a suitable frequency width in this waveform producing device 601,individual differences among piezoelectric elements can be absorbed.

The essential feature of the present invention is the provision of sucha configuration that in order to mix a sample and a reagent with eachother, first, sound waves are irradiated in a direction toward theliquid surface of a solution so as to create a wave at the liquidsurface, and second, sound waves are irradiated to the solution inanother direction in order to enhance the efficiency of the fluidizationof the solution, that is, to efficiently mix the sample and the reagent.In the above-mentioned embodiment, a part of the sound waves irradiatedtoward the liquid surface of the solution and propagated through thereaction container is reintroduced into the reaction container with theuse of the reflector, and accordingly, two way irradiation can bematerialized with the use of a single sound source.

Next, explanation will be hereinbelow made of another embodiment inwhich the irradiation is made in two ways.

Referring to FIG. 7 which shows a second embodiment of the presentinvention, this second embodiment has a configuration similar to thefirst embodiment, comprising a single sound source and a reflector,except that it has a different transmission path 704 through which soundwaves are irradiated to the lower part 706 of the inside of the reactioncontainer. The embodiment shown in FIG. 7 is the same as that of theembodiment shown in FIG. 2 in which the sound waves 701 are irradiatedtoward the liquid surface. However, sound waves 702 irradiated forfluidizing the solution in the bottom part of the reaction container arepropagated outside of the reaction container, as indicated by the arrow704, by means of the reflector 703, and is then introduced into thereaction container so as to create fluidization 705 of the solution inthe bottom part of the reaction container. In this embodiment, as aresult, although two kind of waves are produced from the sound source,with the use of the array-like sound source shown in FIG. 5, theabove-mentioned production of the sound waves can be simply made. Asstated above, even with the configuration shown in FIG. 7, a high degreeof efficiency of mixing similar to that of the embodiment shown in FIG.2 can be obtained.

Further, in another embodiment shown in FIG. 8, which can materializeboth configurations shown in FIG. 2 and 7. That is, it is composed of areflector 803 which reflects sound waves 801 irradiated toward theliquid surface of a solution in a reaction container so as toreintroduce the sound waves into the bottom part of the reactioncontainer, similar to the embodiments shown in FIGS. 2 and 7, and areflector 804 which propagates sound wave outside of the reactioncontainer and then introduces sound waves in the bottom part of thereaction container, similar to the embodiment shown in FIG. 7. With thisconfiguration, it is possible to aim at synergistically fluidizing thesolution in the bottom part of the reaction container.

Although the present invention has been explained in the form of thepreferred embodiments as mentioned above, in which a single sound sourceand a reflector are used, as shown in FIGS. 5 a and 5 b, so as toirradiate sound waves in two directions toward the liquid surface of asolution in the reaction container and the bottom part of the reactioncontainer, respectively, the same technical effects and advantages canbe attained by such a configuration that two sound sources are arranged,independent from each other so as to sound waves are irradiated towardthe liquid surface of the solution in the reaction container and thebottom of the reaction container, respectively. FIG. 9 shows anembodiment having this configuration. In this embodiment shown in FIG.9, sound waves 901 irradiated toward the liquid surface of a solution inthe reaction container are similar to that explained in theaforementioned embodiments, but another sound source 902 is provided,instead of the reflector which is used in the aforementionedembodiments, so as to irradiate sound waves 903 toward the bottom partof the reaction container.

It is noted that the reflector is an important component, in addition tothe sound source, in any of the embodiments shown in FIGS. 2, 7, 8 and10. In general, the greater the difference in acoustic impedance (whichis the product of a density of a medium and a sound velocity) betweentwo media at the interface therebetween, the higher the reflectivity.Thus, in the embodiments of the present invention, the reflectors forreflecting sound waves propagated through the water 204 (in the constanttemperature bath 204) are made of SUS. However, it may be made of any ofmaterials which satisfy the above-mentioned condition, that is, a greatdifference in the acoustic impedance between water and the material,instead of SUS.

In the embodiments stated hereinabove, the sound source composed of apiezoelectric element with divided electrode pieces arranged in an arrayis used, as shown in FIGS. 5 a and 5 b, in order to control the soundwave irradiating position which depends upon a liquid quantity, that is,a liquid surface height which is different among inspection items.However, it goes without saying that a sound source incorporating ashift mechanism, as shown in FIG. 10, may be used, instead of theabove-mentioned sound source. In the embodiment shown in FIG. 10, thevertical shift 102 and the fanning 103 thereof can be controlled, andaccordingly, the direction of sound waves to be irradiated toward theliquid surface of a solution in the reaction container can be optionallyadjusted. Since the direction of the sound waves irradiated toward theliquid surface can be adjusted, thereby it is possible to optimumlycontrol the waveform created at the liquid surface.

Further, in the embodiments which have been hereinabove explained, thesound waves are irradiated in two or three directions. It may beirradiated in much more directions.

Although there have been explained in the above-mentioned embodimentsthe configuration of the agitation for mixing a sample and a reagent ina noncontact manner, this configuration may also be effective forfluidization of washing liquid in a reaction container which is washedby the washing mechanism 111 shown in FIG. 1.

The present invention can be materialized as an analysis device such asa biochemical analysis apparatus, an immune analysis apparatus, a DNAanalysis apparatus or the like, a medicine preparing apparatus or anagitating apparatus.

According to the present invention, it is possible to provide a chemicalanalysis apparatus which can be efficiently agitate a substance to beagitated.

It should be further understood by those skilled in the art thatalthough the foregoing description has been made on embodiments of theinvention, the invention is not limited thereto and various changes andmodifications may be made without departing from the spirit of theinvention and the scope of the appended claims.

1. A chemical analysis apparatus in which a sample to be analyzed and a reagent are placed into a reaction container, and sound waves are irradiated to said reaction container so as to agitate them, wherein said chemical analysis apparatus comprises a piezoelectric element producing said sound waves, and drivers for driving said piezoelectric element, said sound waves being intermittently irradiated into said reaction container.
 2. A chemical analysis apparatus according to claim 1, wherein a voltage which is moderated in amplitude from said drivers is applied to said piezoelectric element.
 3. A chemical analysis apparatus according to claim 1, wherein a voltage which is sinusoidally moderated in amplitude from said drivers is applied to said piezoelectric element.
 4. A chemical analysis apparatus according to claim 1, wherein a voltage which is rectangularly moderated in amplitude from said drivers is applied to said piezoelectric element.
 5. A chemical analysis apparatus according to claim 1, wherein said drivers comprise a wave form producing device for producing an oscillation waveform having a fundamental frequency of said sound waves to be irradiated, an auxiliary waveform producing device for producing an oscillation wave form having a frequency lower than that of said oscillation waveform, a multiplying circuit for creating a multiplied waveform between both of said waveforms, and a power amplifier for power-amplifying the multiplied waveform.
 6. A chemical analysis apparatus in which a sample to be analyzed and a reagent are placed into a reaction container, and sound waves are irradiated to said reaction container so as to agitate them, wherein said sound waves are converged in said reaction container to increase intensity of the sound waves, and a circulation flow created in said sample agitates said sample.
 7. A chemical analysis apparatus according to claim 6, wherein said sound waves are intermittently irradiated into said reaction container. 